Police in Spain's Basque country have arrested 13 people suspected of collaborating with the Basque separatist group ETA. Several of those arrested worked for a human rights group that reportedly served as a front for ETA's activities.

About 200 security agents carried out simultaneous pre-dawn raids in the three provinces of Spain's Basque country and in the neighboring region of Navarre.

Arrested in the operation were 13 people accused of collaborating with ETA. All of them are directors of the group Gestoras-pro-Amnestia, which campaigns for the release of imprisoned ETA activists. Most of them are also members of Batasuna, ETA's political wing.

The ostensible purpose of the pro-amnesty group is to offer moral and financial support for several hundred members of ETA who are imprisoned throughout Spain.

In a news conference Wednesday, Spain's interior minister, Mariano Rajoy, said the pro-amnesty members arrested by police were an integral part of ETA's infrastructure. Mr. Rajoy said they provided logistical support for ETA's operations as well as economic support for ETA members hiding in foreign countries.

The pro-amnesty group is also accused of serving as the main communication link between the separatist organization and its prisoners. The interior minister said the group funneled money to prisoners and also threatened ETA prisoners who were tempted to cooperate with authorities in exchange for commutation of their sentences.

Mr. Rajoy said that the group had received around 23 million pesetas ($125,000) in funding from the Basque regional government, which is controlled by the pro-independence but moderate Basque Nationalist Party.

ETA has admitted responsibility for 35 killings since it called off a 14-month truce at the end of 1999. Since it began its campaign for Basque independence in 1968, it is blamed for the deaths of more than 800 people.